Reservations AIR India not refunding my money.

I paid to AIR India using web access ,US $700 on on July 14,2018 for an upgrade from economy to business class ticket. When I arrived at the Newark airport on July 24,2018 to board Flight AI 144 on that day,no business class seats were available. I have been trying repeatedly since to reach Air India on their US customer service line to find out why my money was not refunded. The lines are are always busy an I go on hold forever. I usually give up after one hour. Does anyone know how to get my money back?